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Strong Quantum Fluctuation of Vortices in Bulk Samples of the New Superconductor MgB2
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| WEN Hai-Hu;LI Shi-Liang;ZHAO Zhi-Wen;NI Yong-Ming;REN Zhi-An;CHE Guang-Can;YANG Hai-Peng;LIU Zhi-Yong;ZHAO Zhong-Xian
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| National Laboratory for Superconductivity,
Institute of Physics and Center for Condensed Matter Physics,
Chinese Academy of Sciences, Beijing 100080 |
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| Cite this article: |
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WEN Hai-Hu, LI Shi-Liang, ZHAO Zhi-Wen et al 2001 Chin. Phys. Lett. 18 816-819 |
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Abstract By using transport and magnetic measurement, the upper critical field Hc2(T) and the irreversibility line Hirr(T) has been determined. A big separation between Hc2(0) and Hirr(0) has been found showing the existence of a quantum vortex liquid state induced by quantum fluctuation of vortices in the new superconductor MgB2. Further investigation on the magnetic relaxation shows that both the quantum tunneling and the thermally activated flux creep depends weakly on temperature. However, when the melting field Hirr is approached, a drastic rise of the relaxation rate is observed. This may indicate that the melting of the vortex matter at a finite temperature is also induced by the quantum fluctuation of vortices.
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| Keywords:
74.25.Bt
74.20.Mn
74.40.+k
74.60.Ge
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Published: 01 June 2001
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